Among the evening's highlights were encounters with mole people - mythical mutants born in the subways - and a run-in with a sewer alligator. All were part of the Halloween scene at Nightmare New York, a haunted house for adults.

With Hollywood-grade stagecraft and professional actors, haunted houses are in increasingly high demand. One in five Halloween celebrants over the age of 18 plans to visit one this year, up from one in six in 2005, National Retail Federation figures show. There are about 2,000 haunted houses charging admission in the United States, according to HauntWorld magazine.

Nightmare welcomes about 35,000 annual visitors, each of whom pays up to $60 to take part in scenes from New York's darkest days, featuring characters, real or imaginary, from outsize rats said to be spawned by Hurricane Sandy to the 1970s serial killer David Berkowitz, better known as the Son of Sam.

Behind-the-scenes control systems cue lighting, sound and animatronics through pressure plates and motion sensors, said David Hinkle, Nightmare's production designer.

At a recent performance, a raggedy wide-eyed man shouted: "Get out of here. I was eating rat!" sending two female visitors into a frenzy.

Patrons who choose the "extra-crispy experience" paint a fake-blood cross on their foreheads, giving permission to the show's more than 35 actors to break the customary no-touching rule.
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